The present invention relates to an electric blower and a vacuum cleaner using the electric blower.
A conventional electric blower is described with reference to FIG. 46.
Impeller 1 comprises rear shroud 2, front shroud 3 which faces the rear shroud 2, and a plurality of blades 4 disposed between the pair of shrouds 2, 3. Inducer part 5 defines an extending part on inlet hole 13 side of blades 4 and a three-dimensional-shaped curved surface, while the outer periphery of blade 4 has a two-dimensional-shaped curved surface. Electric motor 6 drives impeller 1. Air guide 7 having a plurality of stationary blades 8 defines a volute chamber between adjacent stationary blades 8. Fan case 10 includes impeller 1 and air guide 7, is airtightly mounted to the outer periphery of electric motor 6, and has an intake opening 11 in its central part.
An operation in this structure is described. When impeller 1 is rotated by electric motor 6 at a high speed, air flow is sucked from inlet hole 13 of impeller 1, travels through blades 4 without being disturbed by inducer part 5, and is exhausted from the outer periphery of impeller 1. The air flow axially comes into inlet hole 13, but goes out from an outlet of impeller 1 in the centrifugal direction, namely orthogonally to the axial direction. The direction of the air flow changes along the three-dimensional-shaped curved surface of inducer part 5. The air flow further travels through the volute chamber formed from the plurality of stationary blades 8 mounted to air guide 7, and goes into electric motor 6.
As problems of this conventional electric blower, it is difficult to manufacture and has poor productivity because blades 4 include complex-shaped inducer part 5 having the three-dimensional-shaped curved surface. When the blades 4 are manufactured in a cutting work, a very long working time is required, and even when it is manufactured in a molding work, a special manufacturing method is required which makes the blades expensive. A method in which blades 4 are assembled separately from inducer part 5 is also proposed, but there are many requirements, such as easy manufacturing of inducer 5, joining of inducer 5 to blades 4 so that there is less air leakage and without causing air resistance, and fixing of the inducer 5 that it withstands high speed rotation and does not cause any air leakage between both shrouds 2, 3 and the inducer 5. Therefore, this method has not yet commercialized.
The present invention addresses the problems discussed above and aims to provide an electric blower. In this electric blower, a blade of an impeller is divided as a two-dimensional curved-surface-shaped blade and a three-dimensional curved-surface-shaped inducer, and they are constituted as separate components. In addition, problems of strength, clearance, and air resistance are solved, the manufacturing method is simple, and loss is reduced.
For solving the problems discussed above, the electric blower in accordance with the present invention and a vacuum cleaner using it include an electric motor having a rotating shaft and an impeller fixed to the rotating shaft for rotation. The impeller comprises the following elements:
a rear shroud fixed to the rotating shaft;
a front shroud that faces the rear shroud and has an inlet hole to take in air;
a plurality of blades disposed between the rear shroud and the front shroud; and
an inducer which streamlines air flowing from the inlet hole and has a three-dimensional-shaped vane.
The inducer is formed separately from the blade. Thus, a practical electric blower that is simple in structure, least in clearance between parts, higher in strength, lower in loss is realized. An efficient vacuum cleaner high in sucking capacity is realized by the utilization of the electric blower.
A first embodiment of the present invention is an electric blower comprising an electric motor having a rotating shaft and an impeller fixed to the rotating shaft for rotation. The impeller comprises the following elements:
a rear shroud fixed to the rotating shaft;
a front shroud that faces the rear shroud and has an inlet hole to take in air;
a plurality of blades disposed between the rear shroud and the front shroud; and
an inducer which streamlines air flowing from the inlet hole and has a three-dimensional-shaped vane. The inducer is formed separately from the blade and is placed between the rear shroud and the front shroud. The impeller that includes the inducer having a complex shape and has no problem in strength is realized in a simple and mass-producible method. As a result, a downsized, powerful, and highly efficient electric blower can be provided in a lower price.
A second embodiment of the present invention is an electric blower according to the first embodiment, wherein a rear shroud and a front shroud are respectively formed from sheet metals, and an inducer is formed from a moldable material. The high-performance electric blower can be realized in a lower price similar to the first embodiment, by forming the inducer in a resin molding and constituting blades and shrouds with sheet metals.
A third embodiment of the present invention is an electric blower according to the second embodiment, wherein an inducer is molded using a plurality of divided dies that slide substantially radially. The resin made inducer has a shape such that it can be manufactured with slide dies, and therefore, the electric blower having higher mass-productivity can be realized.
A fourth embodiment of the present invention is an electric blower according to the second embodiment or the third embodiment, wherein a number of vanes and a number of the blades are respectively equal to six. The highest efficient condition is selected, and therefore, the highly efficient electric blower having higher mass-productivity can be realized.
A fifth embodiment of the present invention is an electric blower according to the third embodiment, wherein the direction of a line between a point at the tip of a vane of an inducer and a point moved by a clearance from the end of the outer periphery of the vane is matched to a sliding direction of a die. The resin made inducer can be molded in a simple die structure, and the highly efficient electric blower having higher mass-productivity can be realized.
A sixth embodiment of the present invention is an electric blower according to one of the second embodiment to the fifth embodiment, wherein an inducer comprises a substantially conical hub and a plurality of vanes that are fixed to the outer periphery of the hub and have a three-dimensional-shaped curved surface. Furthermore, a parting line generated during molding is formed so that the upstream side of air flow is higher and the downstream side is lower. The electric blower in which resistance of air flow is reduced and efficiency is higher can be realized since the parting line of the inducer that is generated during molding has a step where the upstream side of air flow is higher and the downstream side is lower.
A seventh embodiment of the present invention is an electric blower according to one of the second embodiment to the sixth embodiment, wherein a connecting portion for connecting with the end of a blade is placed at the blade-side end of an inducer. The connecting portion is placed on the inducer for connecting a vane of the resin-made inducer with the blade formed from a sheet metal, leakage of air flow from a joint portion is reduced, and the highly efficient electric blower can be realized.
An eighth embodiment of the present invention is an electric blower according to the seventh embodiment, wherein a recessed part for receiving an end of the blade is drilled in a connecting portion. The electric blower in which leakage is further reduced and an impeller is easily assembled can be realized since the connecting portion of an inducer has a recessed shape.
A ninth embodiment of the present invention is an electric blower according to the eighth embodiment, wherein an end of a metallic blade is pressed into the recessed part. Because the vanes of an inducer are joined with the blade in pressing-in and grabbing methods, the blade can be held together with the inducer during the assembling work of an impeller, and the electric blower easy in assembling work, less in loss, and high in assembling workability can be realized.
A tenth embodiment of the present invention is an electric blower according to the seventh embodiment, wherein the connecting portion is brought into contact with a reversely-rotated side surface of the end of a blade. The connecting portion abuts to one side of the blade, and the abutting direction is matched to the pressure-contact direction of the blade with rotation of an impeller. Thus, resistance of flow is reduced, a joint with reduced leakage is produced, and therefore, the highly efficient electric blower can be realized.
An eleventh embodiment of the present invention is an electric blower according to the seventh embodiment, wherein the connecting portion and the inlet-side end of a blade are integrally formed. Since the connecting portion and the inlet-side end of the sheet-metal-made blade are integrally formed, the assembling is noticeably facilitated, resistance and leakage of air flow can be extremely reduced, and therefore the highly efficient electric blower having higher mass-productivity can be realized.
A twelfth embodiment of the present invention is an electric blower according to the second embodiment, wherein an inducer comprises a hub and a plurality of vanes that are fixed to the outer periphery of the hub and have a three-dimensional-shaped curved surface, an engaging portion is formed on a rear shroud side of the hub, and an engaged portion for engaging with the engaging portion is formed on the rear shroud. The engaging portion is formed on the rear surface shroud side of the hub, and the engaged portion is formed on the rear surface shroud to allow positioning of the inducer, and a clearance between the vanes formed on the inducer and a metal-board-made blade can be reduced. Thus, because the occurrence of loss caused by leakage of air flow to adjacent passages in the impeller can be restrained and pressure can be raised smoothly, the electric blower higher in sucking performance can be realized.
A thirteenth embodiment of the present invention is an electric blower according to the twelfth embodiment, wherein an engaging portion is formed as a boss and the engaged portion is formed as a hole. Because a plurality of bosses capable of engaging with a plurality of holes formed in the rear shroud are deposited on the rear shroud side of a hub of an inducer, a clearance between a vane formed on the inducer and a plate-metal-made blade can be reduced, and an effect as discussed above is obtainable.
A fourteenth embodiment of the present invention is an electric blower according to the twelfth or thirteenth embodiment, wherein a number of engaging portions and a number of engaged portions are respectively equal to a divisor of the number of the blades or the vanes. The number of bosses formed on the rear shroud side of the hub of the inducer and the number of the holes formed in the rear shroud are respectively set equal to the divisor of number of the blades or the vanes. Therefore, the positions of each vane and each blade are matched with each other even if the inducer is embedded at any angle, a clearance between the vane and the blade can be reduced, an effect as discussed above is obtainable, and assembling ability is improved.
A fifteenth embodiment of the present invention is an electric blower according to the second embodiment, wherein an inducer comprises a hub and a plurality of vanes that are fixed to the outer periphery of the hub and have a three-dimensional-shaped curved surface, and a space portion is formed on the rear shroud side of the hub so that thickness of the hub is substantially uniform. Since the space portion is placed on the side abutting to the rear shroud of the hub constituting the inducer so that thickness of the hub is substantially uniform, an inducer that is prevented from deforming due to resin""s distortion occurring during molding and is accurate in size can be realized. Thus, a clearance at a connecting portion between the vane and a blade can be also reduced, and the effect as discussed above is obtainable.
A sixteenth embodiment of the present invention is an electric blower according to the fifteenth embodiment, wherein a plurality of ribs are radially placed in a space portion on a hub of an inducer so as to connect with a boss portion formed in the center of the inducer. Since the ribs are radially placed in the space portion formed on a hub of the inducer, strength of the inducer is increased, positioning and fixing of the inducer are certainly performed during assembling, and the effect as discussed above is obtainable. In addition, centrifugal force and torsion during high speed rotation of an impeller can be prevented from causing deformation or damage of a vane, and the highly reliable inducer can be realized.
A seventeenth embodiment of the present invention is an electric blower according to the sixteenth embodiment, wherein a boss capable of engaging with a hole formed in a rear shroud is formed on at least one of ribs placed in a space portion formed on a hub of an inducer. Thus, strength of the boss is increased, positioning and fixing of the inducer can be certainly performed, and the effect as discussed above is obtainable.
An eighteenth embodiment of the present invention is an electric blower according to the thirteenth embodiment, wherein a tilting portion is formed at the tip of a boss, outer diameter of the root portion of the tilting portion of the boss is made smaller than the diameter of a hole drilled in a rear shroud, and the outer diameter of the root portion of the boss is made larger than the diameter of the hole. Since the tilting portion is formed at the tip of the boss and is made smaller than the outer diameter of the hole, the boss is easily inserted during mounting of an inducer. When the insertion is finished, the inducer is tightly fixed in a state that the root portion of the boss is pressed into the hole. As a result, assembling ability can be further improved, and positioning and fixing of the inducer can be performed.
A nineteenth embodiment of the present invention is an electric blower according to the thirteenth embodiment, wherein a plurality of long holes are drilled in a rear shroud, maximum diameter portion of one of the long holes is made larger than the diameter of a boss, and minimum diameter portion of the other of the long holes is made smaller than the diameter of the boss. Since the plurality of long holes are drilled in the rear shroud, the maximum diameter portion of one of the long holes is made larger than the diameter of the boss, and the minimum diameter portion of the other of the long holes is made smaller than the diameter of the boss, the boss formed on a hub is pressed into the minimum diameter portion by inserting the boss into the hole having the maximum diameter and then rotating an inducer. Therefore, assembling ability can be further improved.
A twentieth embodiment of the present invention is an electric blower according to the second embodiment, wherein recessed parts capable of engaging with a plurality of projecting parts formed on a rear shroud are drilled in a bottom surface of a hub of an inducer which faces the projecting parts. Since the recessed parts are drilled in the bottom surface of the hub of the inducer which faces the projecting parts formed on the rear shroud, the effect as discussed above is obtainable.
A twenty-first embodiment of the present invention is an electric blower according to the second embodiment, wherein a projection is formed on at least one of the upper part and the lower part of the rear edge of a vane of an inducer, an engaging portion capable of joining to the projection is formed at the front edge of a blade, a front shroud and a rear shroud are fixed by simultaneously crimping the projection and the engaging portion. Positioning of the vane of the inducer and the blade can be further performed with certainty.
A twenty-second embodiment of the present invention is an electric blower according to the twelfth embodiment, wherein a boss placed on a hub of an inducer is higher than an engaging portion formed on a blade. Because the boss placed on the hub of the inducer is inserted into a rear shroud prior to the engaging portion formed on the blade, assembling ability of an impeller can be extremely improved.
A twenty-third embodiment of the present invention is an electric blower according to the second embodiment, wherein a through hole is drilled in a position of a front shroud that faces a joint portion between the end of a blade and the end of a vane of an inducer. Because an adhesive can be put through the through hole after assembling of an impeller, a micro clearance of the joint portion can easily be filled. Therefore, occurrence of loss caused by leakage of air flow to adjacent passages in the impeller is restrained, and pressure can be smoothly raised. As a result, the electric blower higher in sucking performance can be realized.
A twenty-fourth embodiment of the present invention is an electric blower according to the second embodiment, wherein a plurality of engaging portions for engaging with a front shroud and a rear shroud are disposed on a blade and at least one of the engaging portions is placed at the inducer side end of the blade. After assembling of the impeller, an adhesive can be made to flow from the engaging portion placed at the inducer side end of the blade and along a joint portion between the blade and a vane, and a micro clearance can be filled easily and certainly. As a result, workability can be improved, and the effect same as that discussed above is obtainable.
A twenty-fifth embodiment of the present invention is an electric blower according to the second embodiment, wherein the distance between the front edge of a blade and the end of an engaging portion formed on the central side of the blade is set shorter than 5 mm. An engaged portion on the central side that is formed in a front shroud can be shifted slightly to the outer periphery side, and the engaging portion and the engaged portion are joined to each other at a slightly moderated curved-shaped part of the front shroud. Therefore, joint strength between the blade and the shroud is increased, and the effect as discussed above is obtainable.
A twenty-sixth embodiment of the present invention is an electric blower according to the twenty-fourth or twenty-fifth embodiment, wherein an engaged portion that can be engaged with an engaging portion on the central side of a blade and is formed in a front shroud is extended toward a suction opening of an impeller. An injection opening of an adhesive is formed in the engaged portion on the central side of the front shroud. The adhesive can be easily made to flow, workability is improved, and the effect as discussed above is obtainable.
A twenty-seventh embodiment of the present invention is an electric blower according to one of the twenty-third to twenty-sixth embodiments, wherein a groove extending from a front shroud to a rear shroud is formed in the end of the rear edge of a vane of an inducer which joins to the front edge of a blade. An adhesive can be made to flow in along the groove, a clearance in a joint portion between the vane and the blade can be certainly filled, occurrence of loss caused by leakage of air flow to adjacent passages in an impeller can be restrained, and pressure can be raised smoothly. As a result, the electric blower higher in sucking performance can be realized.
A twenty-eighth embodiment of the present invention is an electric blower according to the twenty-seventh embodiment, wherein a desired space connected with a groove formed in the end of the rear edge of a vane is placed on the bottom of an inducer. An adhesive can be certainly made to flow into a joint portion between the vane and a blade after assembling of an impeller, and the adhesive, even if it is somewhat excessively made flow, is accumulated in the desired space without going to a place that requires no adhesive. Therefore, a clearance can be effectively filled, and the effect as discussed above is obtainable.
A twenty-ninth embodiment of the present invention is an electric blower according to the second embodiment, wherein a groove is formed from the end to the rear edge of a vane of an inducer that abuts to a front shroud. Not only a joint portion between the vane and a blade, but also a micro clearance in the joint portion between the vane and the front shroud can be filled, occurrence of loss caused by leakage of air flow to adjacent passages in an impeller can be certainly restrained, and pressure can be raised smoothly. As a result, the electric blower higher in sucking performance can be realized.
A thirtieth embodiment of the present invention is an electric blower according to the second embodiment, wherein a through hole is drilled in a position of a rear shroud that corresponds to a joint portion between the end of a blade and the end of a vane of an inducer. When an adhesive is made to flow in through the through hole in the rear shroud, it flows to the joint portion between the blade and the vane and flows to a joint portion between the vane and a front shroud. Therefore, a clearance can be easily filled, workability is improved, and the effect as discussed above is obtainable.
A thirty-first embodiment of the present invention is an electric blower comprising the following elements:
a rear shroud fixed to the rotating shaft of an electric motor;
a front shroud that faces the rear shroud;
a plurality of blades disposed between the pair of shrouds;
an inducer having a plurality of three-dimensional-shaped vanes extending from this blade toward the inlet of an impeller;
a hub defining a base of this inducer; and
a substantially L-shaped notch formed in the root part on the outer periphery side of the vane, of a joint portion between the front edge of the blade and the rear edge of the vane.
The joint portion can abut to a side surface as well as the end surface of the front edge of the blade, and leakage of air flow can be reduced at the joint portion. Since the notch is substantially L-shaped, assembling is facilitated, workability is not lost, and the effect as discussed above is obtainable.
A thirty-second embodiment of the present invention is an electric blower according to the thirty-first embodiment, wherein a flash is formed at the end of a vane joining with a front shroud of an inducer. Since the flash is formed at the end of the vane joining with the front shroud of the inducer, and an impeller is assembled crushing the flexible and thin flash with pressurization during assembling of the impeller, a clearance in a joint surface can be easily closed, and the effect as discussed above is obtainable.
A thirty-third embodiment of the present invention is an electric blower according to the thirty-first embodiment, wherein a micro rib is formed at the front-shroud-side end of a vane of an inducer. Since the micro rib is formed at the end of the vane which joins with the front shroud of the inducer, the flexible micro rib is crushed with pressurization during assembling of an impeller to fill a clearance in a joint surface, and the effect as discussed above is obtainable.
A thirty-fourth embodiment of the present invention is an electric blower according to the thirty-third embodiment, wherein radius Rs of a curved surface of a front shroud which joins with a curve of a vane formed on an inducer and radius Ri of the curve of the vane are set to have the relation Rixe2x89xa6Rs. Since the radius of the curved surface of the front shroud is larger, the front shroud abuts to the periphery of the curve of the vane when the front shroud is pressurized during assembling of an impeller. A clearance in a joint portion can be reduced, and the effect as discussed above is obtainable.
A thirty-fifth embodiment of the present invention is an electric blower according to the thirty-fourth embodiment, wherein height Hi of the rear edge of a vane formed on an inducer and height Hb of the front edge of a blade which joins with the rear edge of the vane is set to have the relation Hixe2x89xa7Hb. Because a front shroud joins to the vane always prior to the blade, no clearance occurs, and the effect as discussed above is obtainable.
A thirty-sixth embodiment of the present invention is an electric blower according to the first embodiment, wherein a front shroud, a rear shroud, an inducer, vanes, and blades are adhered to one another by coating joint surface among them with adhesives. Because clearances that are in each joint portion between the components and are caused by size variation of the components of an impeller can be filled with the adhesives, air leakage from the front or rear part of the blade in the impeller is prevented to improve performance of the impeller.
A thirty-seventh embodiment of the present invention is an electric blower according to the first embodiment, wherein a rear shroud and a front shroud are formed from metal plates and are coated with a coating which melts by heating and gives an adhering effect, namely heating, melting and inter-adhering are performed during an assembling process. Since the front shroud and the rear shroud are previously coated with a coating which melts by heating and gives an adhering effect, the joint portion can be filled by simultaneously heating them during a crimping process of the front and rear shrouds and a blade. Therefore, workability is further improved, and the effect as discussed above is obtainable.
A thirty-eighth embodiment of the present invention is an electric blower according to the thirty-seventh embodiment, wherein an electrostatic coating method or an electrodeposition coating method is used as a coating means. Because an entire impeller can be uniformly coated by employing a coating method using an electrostatic or electrodeposition approach, a clearance can be certainly filled without problem such as reduction of workability or increase of unbalance. Therefore, the effect as discussed above is obtainable.
A thirty-ninth embodiment of the present invention is an electric blower according to the first embodiment, wherein a seal member slidably abutting to an inlet hole of a front shroud is placed on the inner surface of a fan case that faces the inlet hole. Because the seal member is placed in a casing and a suction opening in the front shroud slidably abuts to it to prevent circulation flow, performance of an impeller can be further improved.
A fortieth embodiment of the present invention is an electric blower according to the thirty-ninth embodiment, wherein a part slidably abutting to a seal member in a front shroud and its proximity are not coated. Paint is not put near a suction opening of the front shroud that slidably abuts to the seal member disposed in a casing. Therefore, an increase of frictional resistance due to slidable contact is restrained, and performance of an impeller can be further improved.
A forty-first embodiment of the present invention is a vacuum cleaner having a dust collector for collecting dust, a suction portion communicating with the dust collector, and the electric blower according to one of the first to fortieth embodiments. A highly-effective vacuum cleaner higher in sucking performance can be realized by using the electric blower discussed above for the vacuum cleaner.